When forced to summarize the general theory of relativity in one sentence: Time and space and gravitation have no separate existence from matter.

I am neither especially clever nor especially gifted. I am only very, very curious.

If men as individuals surrender to the call of their elementary instincts, avoiding pain and seeking satisfaction only for their own selves, the result for them all taken together must be a state of insecurity, of fear, and of promiscuous misery.

Marvellous, what ideas the young people have these days. But I don't believe a word of it.

Strange is our situation here on Earth. Each of us comes for a short visit, not knowing why, yet sometimes seeming to divine a purpose. From the standpoint of daily life, however, there is one thing we do know: that man is here for the sake of other men - above all for those upon whose smiles and well-being our own happiness depends.

It is entirely possible that behind the perception of our senses, worlds are hidden of which we are unaware.

I want to know how God created this world. I am not interested in this or that phenomenon, in the spectrum of this or that element. I want to know God's thoughts, the rest are details.